1. Higgs Recoil Study and Higgsino Analysis Friday ILC Group Meeting Dec 18, 2015, KEK Jacqueline Yan (KEK)
2013/07/20 1

2. Features of These Past Weeks
Finalizing papers on Higgs Recoil Analysis and its Model Independence
at this point, all analysis redults should be final
Higgsino pair production studies (with Tanabe-san)
ECM= 500 GeV : χ02 pair , χ01 + χ02, χ±1
benchmarks ILC1 (ΔM ~20 GeV ) and ILC2 (ΔM 〜10 GeV )
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

3. Finalized all analysis of Higgs recoil
Eventually cuts were very much simplified
Signal efficiency is 5-10% higher than results for LCWS2015
bias also reduced
Lepton Pair Candidate Selection
opposite +/- 1 charge
E_cluster / P_total : < 0.5 (μ） / > 0.9 (e)
isolation (small cone energy)
|d0/δd0| < 5 , |z0/δz0| < 5
FSR and bremsstrahlung recovery
Lepton pairing : select pair with smallest χ2(Minv, Mrec)
Final Selection
73 < GeV < M_inv < 120 GeV
10 GeV < pt_dl < 140 GeV
|cos(θ_missing)| < 0.98
TMVA cut
(..) GeV < Mrec < (…) GeV
Evis cut
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

4. Syst error on xsec : σ = N/L/ε :: Δσ/σ= Δε/ε
observe deviation from average efficiency
Cut Efficiency Table 350 GeV, Pol (-0.8,+0.3)
final efficiency in last row
(statistical uncertainty = 0.16%)
no visible bias beyond 1 sigma
Largest bias is carried by Hγγ (or H Z γ)
Bias get smaller for higher ECM
residual bias:
regarding γZ mode :
lepton mis-ID (e<-- μ) : leptons decayed from non-prompt Z got in the way
cosθmissing cut cause some bias , but this cut cannot be sacrificed (see next page)
Regarding γγ mode :
very slight bias for Zee because no extra protection was used in FSR/brem recovery
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

5. Taking into account of unknown exotic decay modes !
any exotic decay modes should resemble these wide kinematic range of SM modes
Strategy:
assign 10% of “unknown mode” to one of the known SM modes
fluctuate remaining SM modes by the largest BR uncertainty predicted from HL-LHC (7-8%) (Ref: snowmass report from higgs working group, arXiv: )
a very pessimistic (conservative) assumption
Here bias is (BR of exotic mode) * (eff of exotic mode - eff_avg)
relative syst error on σZH = maximum bias relative to avg efficiency
< % for Zmm 　　〜 0.19% for Zee
This is the most realistic evaluation of bias !!
conclusion: current systematic error is well below even the best statistical uncertainty expected from full H20 run (〜0.9%)
Then I added all other BG and sig processes that hhave been generated as samples, even though I presumed them to be not important for Zmumu analysis at 250 GeV.
I wanted to check I didn’t msis anything.
I almost didn’t miss anything, except for WW_sl,
Some of the quarks may have decayed secondarily into muons, and I left it out.
There are about 130 events left after all cuts.
While other were mostly 0.
The results were only a little different after including this.
Extensive efforts have been made to reduce systematic error to this stage!!
LCWS2015, J.Yan

6. Cannot Remove Cosθmissing cut !!
there will be significant degradation in precision for most channels
Degradation is more apparent at lower ECM (θmissing more forward)
now we have no Ptsum, no Ptdl in TMVA, so need at least one variable to remove 2f BG
Besides, cosθmissing is not causing huge mode bias
Degrade xsec
Degrade mass
ECM=250 GeV
xsec
mH[MeV]
Zmm
left
3.2% 39
3.6% 45
12.5%
13.8%
right 43
4.1% 49
13.7%
12.2%
Zee
4.0%
121
4.5%
145
13.6%
19.8%
4.7%
149
5.4%
14.6%
0.0%
ECM=350 GeV
mass
3.9%
103
4.2%
112
6.7%
8.7%
120
4.9%
131
9.2%
5.3%
450
5.7%
484
8.4%
7.6%
6.1%
502
545
8.8%
8.6%
ECM=500GeV
6.9%
592
7.2%
610
3.0%
8.1%
660
8.5%
720
5.1%
9.1%
1160
7.5%
1190
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

7. try again at mH measurement using Hbb mode
B likelihood: Red: 2f BG Blue : signal
mH measurement does not need to be model-independent,
If use Hbb mode, the only major residual BG is 4f_zz_sl
Zmm : b-tag
250GeV
ΔmH[MeV]
ΔmH
(H-->bb)
Zmm
left 39 38
right 43
Zee
121
106
149
124
350 GeV
103
114
120
125
450
382
502
464
500 GeV
592
530
660
566
1160
1030
1190
1130
More improvement for Zee
And ECM=500 GeV (10-15%)
no improvement for Zmm at 250, 350 GeV
(2f BG is more serious for Zee and higher ECM)
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.
2f BG is greatly reduced, but mass precisions limited by signal statistics
requires more careful optimisation

8. Quantitative evaluation of the effect of FSR/brem recovery
Difficult to explain the difference in the improvement for each channel
In the case of Zee channel:
precision of σZH cdegraded by as much as 73%,
MH by as much as 23% without the recovery process.
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

9. Higgsino Analysis
Examples of event displays of ILC1 benchmark events (summarized by Tanabe-san)
By now, moved up to analysis stage
before deciding on concrete analysis strategies, we need to perform a thorough check of tools
lepton ID, tracking, beamCal (to veto 2 photon processes), ect….
currently writing code to print out lkinmatic variables and decay patterns into rootfiles
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.
Jenny requested me to upload generated, simulated and reconstructed files and meta data to the grid and register them properly in the ILCDirac catalogue.
(to keep track of large produced samples)

10. Ch1ch1 events ch1  nu1 + Wnu1 + jets semileptonic decay
ch1 nu1 + W  nu1 + leptons
semileptonic decay
This is wanted!
ch1 nu1 + W  nu1 + leptons
leptonic decay
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.

11. nu1nu2 events leptonic decay nu2  nu1 + Z leptons (mm, ee)
This is wanted!
nu2  nu1 + Z leptons (mm, ee)
Invisible, Z decay to nuetrinos
Hadronic decay
nu2  nu1 + Z jets
Here is the data selection I applied, with the numbers from last week Friday.
First I select muon pairs based on ratio of deposit in calorimeter wrt to total energy, opposite charge, and track quality.
Than I pick out the best muon pair candidates base on how close their inv mass is to real Z mass
Next , comes final selection for recoil mass analysis.
Here, in the order that these arei implemented
I require inv mass to be between 86 and 95 GeV,
Then recoil mass to be between 115 and 140 GeV
Then PT of dilepton system to be between 10 GeV and 70 geV
Then acoplanarity to be between 0.2 and 3
then cosine of Z production angle to be smaller than 0.91, to cut out very forward events characteristic of BG processes,
Then I calculate efficieny by counting events in signal region of 123 and 135 geV
Recoil mass is calculated taking into account beam x angle of 14 mrad.
Last week I received a comment from Kurata san about why I have this lower limicoplanarity
Ithe reason is that for some Bgprocesses, teher is a peak at very small cop values, although for the dominant 2f_Z_l, peak is at aroudn pai.
However I have doubts as to whether this cut is really necessary, when I already have the other cuts before it.
experimented with the outcome s when I take away the lower limit, and when I take away the cop cut altogether.
I also experimented with widening the inv maass cut window.